Satisfactory mastery of cardiopulmonary resuscitation (CPR) presupposes adequate training and frequent practice. For that purpose, many forms of dummies are known, which simulate the human upper body including head, to a greater or lesser degree, and which include a lungs simulation which can be the subject of artificial respiration through a mouth and/or nose opening. A significant factor in that respect is that the dummy behaves in a realistic fashion, both in heart massage and also in artificial respiration, that is to say it opposes a resistance to the compression to be performed in effecting heart massage, and experiences a deformation effect which substantially corresponds to the human thorax, while giving expansion of the thorax when artificial respiration is applied which substantially simulates thorax expansion when the lungs of a human being are filled. It is only when the dummy is fashioned to substantially simulate the behavior of the human body that cardiopulmonary resuscitation on such a dummy can be correlated to correct performance in an emergency situation on a human being, for example an accident casualty.
Numerous dummies for learning and practicing CPR are known, which, in a simulation of the human thorax, contain a resilient return element in the form of one or more springs or a pneumatic cylinder, wherein the resilient return element serves for simulation of the resistance which occurs when heart compression is effected, and for returning the thorax to its initial position. In such dummies the lungs are simulated by an inflatable bag which is communicated with the mouth or nose opening of the head by way of a trachea simulation.
A dummy is also already known in which the thorax is formed by an air-tight container which retains its shape and which at the same time forms the lungs and for that purpose is communicated with the mouth or nose opening of the head by way of a trachea simulation. In that arrangement the container is so designed that it simulates the thorax expansion which occurs upon artificial respiration by virtue of a resilient change in its shape, while also corresponding to the compression resistance of a human thorax when heart massage is performed (German patent specification No 2 543 671).
Just like the dummies referred to in the opening part of this specification, in which the thorax resistance is produced by mechanical or pneumatic springs, that known dummy also only provides a compromise, in terms of the behavior of the thorax in heart massage and in artificial respiration, because the air pressure which obtains in the interior of the airtight container is substantially determined by the resistance which occurs in heart massage, and the deformation characteristics involved. In that respect the container differs from the deformation characteristics of the human thorax in regard to its expansion characteristics when being inflated.